6A). Treatment with CRIg-Fc in vivo (treatment from day 1 to day 22 p.i.) led to a marked reduction in in vitro

INF-γ, IL-6, IL-17A, and TNF-α production compared with cells from PBS-treated EAU mice (all cells were stimulated in vitro with 25 μg/mL pIRBP, Fig. 6A). In addition, in vitro treatment of CRIg-Fc also significantly reduced the production of pIRBP-induced IFN-γ, IL-2, IL-6, and IL-17A in cells of PBS-treated EAU mice (Fig. 6B). The production of IL-10, however, was slightly increased by the same concentration of CRIg-Fc (Fig. 6B). Interestingly, the INK 128 production of in vitro pIRBP-induced TNF-α was not affected by CRIg-Fc treatment (Fig. 6B). NO produced by infiltrating macrophages are one of the important mediators of retinal damage in EAU 29, 30. When stimulated with LPS, BM-derived macrophages (BMDM) expressed high levels of iNOS gene

(Fig. 7A) and produced large amounts of NO (Fig. 7B). In vitro CRIg-Fc treatment dose-dependently suppressed iNOS gene expression (Fig. 7A) as well as NO production induced by LPS in BMDM (Fig. 7B). Control protein (anti-gp120, selleck chemicals llc mouse IgG1) showed no effect on either iNOS gene expression (Fig. 7B) or NO production (Fig. 7B). Although complement activation is beneficial in clearing infection and is essential for tissue homeostasis, unregulated complement activation may contribute to the pathogenesis of autoimmune disease. The data reported in this article using EAU as a model disease support this view. During inflammation, complement-mediated damage is well recognised. Complement activation may amplify the inflammatory response not only by the formation of the membrane attack complex (C5b-9), but also by releasing a variety of complement fragments, particularly the anaphylatoxins C3a and C5a. The anaphylatoxin molecules C3a and C5a enhance vascular

permeability (i.e. breakdown of blood–retinal barrier in the retina), promote T-cell costimulatory and survival signals 31, 32, recruit immune cells, activate mononuclear ZD1839 phagocyte, and release inflammatory mediators 33, 34. A more recent study has shown that in the presence of IFN-γ, C5a is able to induce macrophage NO production and contributes to retinal damage in EAU 19. The C5a/C5aR pathway has also been shown to negatively regulate Th17- and Treg-cell differentiation via reduction in TGF-β secretion 35, 36. Dendritic cells deficient in C5aR produce high levels of TGF-β which promotes Treg production, or in the presence of IL-6 and IL-23, promotes the induction of Th17 cells and IL-17-associated inflammatory disease 35. In addition, C5a also promotes γδ T-cell IL-17A production and blocking of C5a with a neutralizing antibody suppresses T-cell IL-17 production 36. Control of complement activation in EAU is likely, therefore, to have beneficial action at multiple levels.